Built by Aabis
Notebook Theme

Experiment No. N

Analysis of Sodium Sulphide ((Na)₂S)

Aim

To determine the presence of anion and cation in the given salt

Preliminary Test

  • Odor: Odor of rotten eggs
  • Texture: Crystalline
  • Color: White
  • Solubility: Soluble in water

Test of Anion

ExperimentObservationInference
Warm the salt with dilute H₂SO₄Colourless gas with smell of rotten eggs is evolvedS²⁻ may be present
Confirmatory Tests
Lead Acetate Test
Pass gas through filter paper dipped in lead acetate solution		Paper turns blackS²⁻ is confirmed
Sodium Nitroprusside Test
Make solution alkaline with NH₄OH (or sodium carbonate extract) and add sodium nitroprusside solution		Purple/violet colouration is producedS²⁻ is confirmed

Test of Cation

ExperimentObservationInference
Flame test in a clean non-luminous flameIntense yellow flameNa⁺ may be present
Confirmatory Test
Zinc Uranyl Acetate Test
Take a filtrate and add zinc uranyl acetate solution		Yellow crystalline precipitateNa⁺ is confirmed

Result

The given salt contains Na⁺ ions as cation and S²⁻ ions as anion. The salt is (Na)₂S.

Precautions

  1. Handle the chemicals with care.
  2. Don't use excess of chemicals.
  3. Keep the mouth of the test tube away from the face.